Multi-Layer Battery Cell Case Structure for Overcurrent Reliability
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Solution Overview
Problem
Existing battery technologies face challenges in improving both the performance and safety of battery cells, particularly in ensuring structural strength and overcurrent capability while maintaining energy density and cycle life.
Innovation Solution
A battery cell design featuring a multi-layer case structure with varying resistivity, where layers with low resistivity enhance overcurrent capability and layers with high resistivity improve structural strength, combined with a barrel and cover connection for electrode terminals, simplifying the structure and facilitating integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-material case structure is used, then the manufacturing process is simple, but both overcurrent capability and structural strength cannot be simultaneously optimized
Solution Approach 1:
The case is divided into multiple layers with different materials and functions. The first case layer (inner layer) is designed with low resistivity for overcurrent capability, while the second case layer (outer layer) is designed with high strength for structural support. This segmentation allows each layer to specialize in its function without compromising the other.
Solution Approach 2:
The patent employs a composite case structure where the first case layer uses materials with low resistivity (such as aluminum or aluminum alloy) and the second case layer uses materials with high strength (such as steel or steel alloy). This composite approach combines the electrical conductivity benefits of aluminum with the mechanical strength benefits of steel, resolving the contradiction between overcurrent capability and structural strength.
2Reliability
If the first case layer thickness is increased to improve overcurrent capability, then electrical performance improves, but structural strength and processing difficulty are affected
Solution Approach 1:
The case thickness requirement is segmented between two layers. The first case layer has a thickness optimized for electrical conductivity (5-15 μm), while the second case layer has a thickness optimized for mechanical strength (0.5-2.0 mm). This segmentation allows each layer to have its thickness independently optimized for its specific function.
Solution Approach 2:
Different regions of the case have different thicknesses and material properties tailored to their specific functions. The inner layer is thinner and more conductive, while the outer layer is thicker and stronger. This local quality approach ensures that material is distributed efficiently according to functional requirements rather than uniformly throughout the entire case.
3Ease of manufacture
If the case structure is simplified for ease of manufacture, then production cost decreases, but overcurrent capability and structural strength cannot be simultaneously optimized
Solution Approach 1:
The patent merges the electrical conductor function and the structural support function into a single integrated case component with two layers. This eliminates the need for separate conductor and structural elements, simplifying the overall manufacturing process while achieving both overcurrent capability and structural strength simultaneously.
Solution Approach 2:
The composite case structure is designed to be manufactured as an integrated component using conventional metal forming and bonding techniques. The first case layer and second case layer are combined through processes such as plating, cladding, or composite forming, which are established industrial methods that do not significantly increase manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances the overcurrent capability and structural strength of the battery cell, prolonging its service life and reducing the risk of thermal runaway, while maintaining energy density and cycle life.
Implementation Method 1
The first tab is electrically connected to the first electrode terminal by using the barrel. The case is of a multi-layer structure. The multi-layer structure has different resistivity.
Implementation Method 2
The first case layer has a resistivity of K1, where K1 satisfies: 1×10^-8 Ω·m≤K1≤6×10^-8 Ω·m. By setting the first case layer included in the case to have a small resistivity K1, the overcurrent capability of the case can be improved
Implementation Method 3
The second case layer has a tensile strength of Rm2 at a temperature of 25°C, where Rm2 satisfies: 250 MPa≤Rm2≤2000 MPa. By setting a large tensile strength Rm2 of the second case layer included in the case at a temperature of 25°C, the structural strength and deformation capability of the case can be improved
Data Source
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AI summary
Embodiments of the present application disclose a battery cell, a battery, and a power consuming device. The battery cell includes an electrode assembly, a first electrode terminal, and a case. The electrode assembly includes a first tab. The case includes a barrel and a cover connected to the barrel. The barrel is disposed around an outer periphery of the electrode assembly. The cover includes the first electrode terminal. The first tab is electrically connected to the first electrode terminal by using the barrel. The case is of a multi-layer structure. The multi-layer structure has different resistivity. According to the battery cell, the battery, and the power consuming device in the embodiments of the present application, the reliability of the battery cell can be improved.